Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes We operate on a global basis and are subject to numerous and complex tax laws and regulations. Additionally, tax laws continue to undergo rapid changes in both application and interpretation by various countries, including state aid interpretations and initiatives led by the Organization for Economic Cooperation and Development. Our income tax filings are subject to examinations by taxing authorities throughout the world. Income tax audits may require an extended period of time to reach resolution and may result in significant income tax adjustments when interpretation of tax laws or allocation of company profits is disputed. Although ultimate timing is uncertain, the net amount of tax liability for unrecognized tax benefits may change within the next twelve months due to changes in audit status, expiration of statutes of limitations, settlements of tax assessments and other events. Management’s best estimate of such change is within the range of a $115 million decrease to a $25 million increase. Our U.S. Federal income tax returns have been audited through 2009 and are currently under audit for years 2010-2015. The IRS has proposed adjustments for years 2005-2012, reallocating profits between certain of our U.S. and foreign subsidiaries. We have disputed these adjustments and intend to continue to vigorously defend our positions. For years 2005-2007, we have filed a petition with the U.S. Tax Court. For years 2008-2012, we are pursuing resolution through the IRS Administrative Appeals Process. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the "2017 Tax Act"). The 2017 Tax Act made changes to the U.S. tax code, which included (1) reducing the U.S. corporate income tax rate from 35 percent to 21 percent, (2) implementing a base erosion and anti-abuse tax, (3) generally eliminating U.S. federal income taxes on dividends from foreign subsidiaries, (4) adding a new provision designed to tax global intangible low-taxed income ("GILTI") of foreign subsidiaries which allows for the possibility of utilizing foreign tax credits to offset the tax liability (subject to some limitations), (5) implementing a lower effective U.S. income tax rate on certain revenues from sources outside the U.S., and (6) implementing a one-time transition tax on certain undistributed earnings of foreign subsidiaries. In the year ended December 31, 2017, we recorded a provisional discrete net tax benefit associated with the 2017 Tax Act and related matters. As of September 30, 2018, the amounts recorded for the 2017 Tax Act remain provisional for the transition tax, the remeasurement of deferred taxes, and our reassessment of permanently reinvested earnings, uncertain tax positions and other related matters. These estimates may be impacted by further analysis and future clarification and guidance regarding available tax accounting methods and elections, earnings and profits computations, state tax conformity to federal tax changes and the impact of the GILTI provisions. We have not yet determined our policy election with respect to whether to record deferred taxes for basis differences expected to reverse as a result of the GILTI provisions in future periods or use the period cost method. We have, however, included an estimate of the current GILTI impact in our tax provision for 2018. In the three and nine month periods ended September 30, 2018, our effective tax rate (“ETR”) was negative 5.5 percent and positive 12.1 percent, respectively. In the three and nine month periods ended September 30, 2018, we recognized tax benefits resulting from return to provision adjustments related to changes in estimated tax rates on deferred tax liabilities recorded on acquisition-related intangible assets. The change in estimates from these adjustments resulted in tax benefits of $16.9 million in the three and nine month periods ended September 30, 2018. In the prior year periods, we had certain discrete adjustments that significantly impacted our ETR. In the nine month period ended September 30, 2017, we recognized a tax benefit of $69.7 million resulting from a tax restructuring that lowered the tax rate on certain deferred tax liabilities recorded on intangible assets recognized in acquisition-related accounting. In the three and nine month periods ended September 30, 2017, we recognized tax benefits of $39.8 million and $128.6 million, respectively, related to resolution of certain tax matters. In addition, our prior year ETR was affected by the significant expenses associated with the Biomet merger and other acquisitions which have generally been recognized in higher income tax jurisdictions. Accordingly, this has reduced our ETR as our earnings have been lower in these higher income tax jurisdictions.

11. Income Taxes

We operate on a global basis and are subject to numerous and complex tax laws and regulations. Additionally, tax laws continue to undergo rapid changes in both application and interpretation by various countries, including state aid interpretations and initiatives led by the Organization for Economic Cooperation and Development. Our income tax filings are subject to examinations by taxing authorities throughout the world. Income tax audits may require an extended period of time to reach resolution and may result in significant income tax adjustments when interpretation of tax laws or allocation of company profits is disputed. Although ultimate timing is uncertain, the net amount of tax liability for unrecognized tax benefits may change within the next twelve months due to changes in audit status, expiration of statutes of limitations, settlements of tax assessments and other events. Management’s best estimate of such change is within the range of a $115 million decrease to a $25 million increase.

Our U.S. Federal income tax returns have been audited through 2009 and are currently under audit for years 2010-2015. The IRS has proposed adjustments for years 2005-2012, reallocating profits between certain of our U.S. and foreign subsidiaries. We have disputed these adjustments and intend to continue to vigorously defend our positions. For years 2005-2007, we have filed a petition with the U.S. Tax Court. For years 2008-2012, we are pursuing resolution through the IRS Administrative Appeals Process.

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the "2017 Tax Act"). The 2017 Tax Act made changes to the U.S. tax code, which included (1) reducing the U.S. corporate income tax rate from 35 percent to 21 percent, (2) implementing a base erosion and anti-abuse tax, (3) generally eliminating U.S. federal income taxes on dividends from foreign subsidiaries, (4) adding a new provision designed to tax global intangible low-taxed income ("GILTI") of foreign subsidiaries which allows for the possibility of utilizing foreign tax credits to offset the tax liability (subject to some limitations), (5) implementing a lower effective U.S. income tax rate on certain revenues from sources outside the U.S., and (6) implementing a one-time transition tax on certain undistributed earnings of foreign subsidiaries. In the year ended December 31, 2017, we recorded a provisional discrete net tax benefit associated with the 2017 Tax Act and related matters. As of September 30, 2018, the amounts recorded for the 2017 Tax Act remain provisional for the transition tax, the remeasurement of deferred taxes, and our reassessment of permanently reinvested earnings, uncertain tax positions and other related matters. These estimates may be impacted by further analysis and future clarification and guidance regarding available tax accounting methods and elections, earnings and profits computations, state tax conformity to federal tax changes and the impact of the GILTI provisions. We have not yet determined our policy election with respect to whether to record deferred taxes for basis differences expected to reverse as a result of the GILTI provisions in future periods or use the period cost method. We have, however, included an estimate of the current GILTI impact in our tax provision for 2018.

In the three and nine month periods ended September 30, 2018, our effective tax rate (“ETR”) was negative 5.5 percent and positive 12.1 percent, respectively. In the three and nine month periods ended September 30, 2018, we recognized tax benefits resulting from return to provision adjustments related to changes in estimated tax rates on deferred tax liabilities recorded on acquisition-related intangible assets. The change in estimates from these adjustments resulted in tax benefits of $16.9 million in the three and nine month periods ended September 30, 2018. In the prior year periods, we had certain discrete adjustments that significantly impacted our ETR. In the nine month period ended September 30, 2017, we recognized a tax benefit of $69.7 million resulting from a tax restructuring that lowered the tax rate on certain deferred tax liabilities recorded on intangible assets recognized in acquisition-related accounting. In the three and nine month periods ended September 30, 2017, we recognized tax benefits of $39.8 million and $128.6 million, respectively, related to resolution of certain tax matters. In addition, our prior year ETR was affected by the significant expenses associated with the Biomet merger and other acquisitions which have generally been recognized in higher income tax jurisdictions. Accordingly, this has reduced our ETR as our earnings have been lower in these higher income tax jurisdictions.